1. Field of the Invention
This invention relates to the automation of transport of construction materials on a building site, and more particularly, to the automation of a horizontal transport process.
2. Description of the Related Art
An example of this type of device is discussed in, for example, Mitsubishi Heavy Industry Technical Reports Vol. 29, No. 5. p.424-p427. This report gives an overall description of the picking up of loads, setting down of loads and transportation, but herein the prior art automation of horizontal transport will be mainly discussed. FIG. 11 is a simplified diagram of an autonomous guided vehicle essentially illustrating the horizontal transport function. In FIG. 11, 1 is an autonomous guided vehicle, 2 is a radio, 3 is a travel trace sensor, and 4 is a travel tape attached to the surface of a work floor. FIG. 12 is a diagram showing a form of automated horizontal transport according to the prior art. In this figure, 1, 2 are identical to FIG. 11. 5 is a work floor column, 6 is a temporary elevator for vertical transport, 7 is a work floor, 8 is a transport path provided on the work floor, 9 is an obstacle such as a construction tool, 10 is a step which is an obstacle to the travel of the autonomous guided vehicle, 11 is an obstacle such as window glass, 12 is an opening in the floor surface, 13 is an obstacle such as a lightweight concrete wall board, 14 is an object to be transported, 15 is a computer for controlling the autonomous guided vehicle 1, 16 is a radio for sending a signal to the autonomous guided vehicle 1, 17 is a CRT for displaying the output of the computer 15, 16 is a tenkey pad for input to the computer 15, and 19 is a control console integrating the computer 15, radio 16, CRT 17 and tenkey pad 18 which is normally installed in a control room at floor level. FIG. 13 is a block diagram showing the construction of the control system. The symbols 1,2, and 15-19 in the figure are identical to those in FIG. 12.
Next, the operation of this system will be described with reference to the example of FIG. 12 and the block diagram of FIG. 13. A material which has been vertically transported to the work floor by the temporary elevator 6 is loaded onto a loading platform of the autonomous guided vehicle by a worker in front of the elevator. According to a command from the computer 15, the loaded autonomous guided vehicle 1 is guided along the travel tape 4 shown in FIG. 11 to a position where the load is to be unloaded. When the vehicle moves, the light reflected from the travel tape is detected by the travel trace sensor 3 shown in FIG. 11, and any deviation of the autonomous guided vehicle 1 from the travel tape 4 is determined. The deviation is corrected by controlling the left/right steering of the vehicle wheels according to the deviation amount so that the vehicle travels along the travel tape attached to the floor surface.
A command is sent to the autonomous guided vehicle 1 from the computer 15 in the control console 19 installed on the ground floor. Also, signals are sent from the autonomous guided vehicle 1 to the computer 15 via the radios 2 and 16 as necessary. The layouts of all the floors, and the positions at which materials are loaded and unloaded, are previously stored in the computer 15. The computer 15 extracts stored information as necessary according to transport commands input from the tenkey pad 18, and controls the motion of the autonomous guided vehicle 1 accordingly. Loading/unloading data and work completion data from the autonomous guided vehicle 1 is displayed on the CRT 17.
In the aforesaid prior art system, the travel tape 4 was an essential feature for guiding the autonomous guided vehicle. However, the travel tape must be removed when laying floors in the building site, and it can be used in only a limited number of construction processes. Loading/unloading can be performed only on routes where the travel tape is laid on the floor so the transporting of materials lacked flexibility, and it was therefore difficult to use the autonomous guided vehicle more efficiently in building site operations where work floors are constantly being replaced according to the nature of the operation.
For aligning a plurality of materials at a specific point, special path settings and complex programming were required, which was troublesome.
Moreover, dust from materials transported on site and mud brought in on materials from outside soils the travel tape, causing the autonomous guided vehicle to operate erroneously so that it cannot be controlled.